Toilet apparatus

ABSTRACT

According to one embodiment, a seating detection sensor includes a strain generating body and a strain gauge. The strain generating body is held on a casing or a toilet seat. The strain generating body receives a load from the toilet seat via a shaft portion to generate a strain. The strain gauge is provided on the strain generating body and detects a strain amount of the strain generating body. A force release portion releases a force applied to an opening in a horizontal direction from the shaft portion in a state of the shaft portion abutting the opening so that the force is not converted downwardly in a vertical direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-188653, filed on Sep. 27, 2016; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a toilet apparatus.

BACKGROUND

At the present time, a toilet apparatus including seating detectionfunction using a micro switch is released. In the configuration based onthe micro switch like this, a user feels strange by sinking the toiletseat when seated, and it sounds like a clicking sound with a smallvolume, and then quality of level is left to be improved.

Here, it is conceived that seating detection is performed by using astrain gauge. For example, JP H06-88371 A (Kokai) discloses theconfiguration where the strain gauge is attached to a back surface ofthe toilet seat, a hinge portion or the like. JP 2000-254040 A (Kokai)discloses the configuration where a load detection means formed of astrain gauge is provided in the toilet seat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of a toilet apparatus of an embodiment, and FIG.1B is an enlarged view of a state in which a toilet seat is removed inportion A of FIG. 1A;

FIG. 2 is a perspective view of a portion shown in FIG. 1B as viewedfrom right side;

FIG. 3 is an A-A cross sectional view in FIG. 1B;

FIG. 4 is an enlarged view of a portion B in FIG. 3;

FIG. 5 is a B-B cross sectional view in FIG. 1B;

FIG. 6A is an enlarged view of an opening formation portion in a casingof the embodiment, and FIG. 6B shows insertion of a shaft portion of thetoilet seat into the opening of FIG. 6A;

FIGS. 7A and 7B are perspective views of a position shift absorptionmember of the embodiment;

FIG. 8 is a perspective view of the position shift absorption member, astrain generating body, and a strain gauge of the embodiment;

FIG. 9 is a circuit block diagram of the toilet apparatus of theembodiment;

FIG. 10A is a view similar to FIG. 4 showing a hinge portion of theembodiment, and FIGS. 10B and 10C are views of comparison examples toFIG. 10A;

FIGS. 11A and 11B are schematic views showing movement in a front-backdirection of a user seating on the toilet seat;

FIGS. 12A to 12C are schematic views showing other examples of theopening formed in the casing of the embodiment; and

FIG. 13A is a schematic cross sectional view along a vertical directionof a hinge portion of other embodiment, and FIG. 13B is a partial crosssectional side view as viewing a left side to a D-D line in FIG. 13A.

DETAILED DESCRIPTION

The load applied to the toilet seat on user seating is easily smallerthan a back surface of the toilet seat in a hinge portion. If seating isintended to detect by providing a strain gauge on the hinge portion,when the same strain gauge and strain generating body are used, thestrain generating body is hard to deflect compared with the case ofproviding the strain gauge on the back surface of the toilet seat, andthen the output of the strain gauge provided on the strain generatingbody becomes small.

That is, since the output of the strain gauge provided on the hingeportion is small, the load due to movement of the toilet seat in afront-back direction accompanied with weight shift of the userinfluences largely load detection in a vertical direction.

If it is conceived that the seating is intended to be detected invarious seating of various people, for example, it is desired that thestrain generating body is easy to be deflected so as to detect theseating and the output of the strain gauge is made large even if a childsits on a front of the toilet seat, however on the other hand, there isa fear that when a grown-up shifts the weight on the toilet seat, thestrain generating body is broken by a larger load applied to the straingenerating body than expected.

A toilet apparatus of a first invention comprising: a casing; a toiletseat attached rotatably to the casing, an opening being provided on oneof the casing or the toilet seat, a shaft portion being provided on oneother of the casing or the toilet seat, the shaft portion being insertedinto the opening, the shaft portion being capable of abutting theopening by movement of the toilet seat in a front-back direction; aseating detection sensor detecting seating of an user on the toiletseat, the seating detection sensor including a strain generating bodyand a strain gauge, the strain generating body being held on the casingor the toilet seat, the strain generating body receiving a load from thetoilet seat via the shaft portion to generate a strain, the strain gaugebeing provided on the strain generating body and detecting a strainamount of the strain generating body; and a force release portionreleasing a force applied to the opening in a horizontal direction fromthe shaft portion in a state of the shaft portion abutting the openingso that the force is not converted downwardly in a vertical direction.

According to the first invention, the load applied in the verticaldirection to the strain generating body when the user seats on thetoilet seat is not influenced by the load due to the weight shift or thelike of the user, and since the original vertical load is surely appliedto the strain generating body, it is possible to detect surely seatingof the user on the toilet seat. Since there is no conversion from thehorizontal load to the vertical load, the excessive load is not appliedto the strain generating body, and it is possible to prevent thebreakage of the strain generating body and the strain gauge.

According to a toilet apparatus of a second invention, the opening isprovided in the casing, the shaft portion is provided in the toiletseat, and the strain generating body is held to the casing below theshaft portion.

According to the second invention, it is possible to provide the seatingdetection sensor on the hinge portion without changing the existingconfiguration largely.

According to a toilet apparatus of a third or fourth invention, theforce release portion maintains a force applied from the shaft portionto the strain generating body in a vertical direction in a state of theshaft portion not abutting the opening also in a state of the shaftportion abutting the opening.

According to the third or fourth invention, it is possible to eliminatealmost no noise of the vertical load applied to the strain generatingbody, and setting of correlation between the load applied to the straingenerating body and the output of the strain gauge becomes easy.

According to a toilet apparatus of a fifth or sixth invention, the forcerelease portion is a vertical surface of the opening, the shaft portionbeing capable of abutting the vertical surface.

According to the fifth or sixth invention, even if the shaft portionabuts the side face (vertical surface), the shat portion receives justonly a reaction force in the horizontal direction from the opening, anddoes not receives the force in the vertical direction. Therefore, theforce applied in the vertical direction to the strain generating bodyfrom the shaft portion in a state of the shaft portion not abutting theside face of the opening does not change also in a state of the shaftportion abutting the side face of the opening, and is maintained.

According to the invention, it is possible to improve a seatingdetection performance against a small load and to prevent breakage ofthe strain generating body and the strain gauge due to a large loadwhile improving a quality by providing the seating detection sensorusing the strain gauge at the hinge portion.

Various embodiments will be described hereinafter with reference to theaccompanying drawings. The same numerals are applied to similarconstituent elements in the drawings.

FIG. 1A is a top view of a toilet apparatus 10 of an embodiment.

The toilet apparatus 10 of the embodiment includes a casing 11 and atoilet seat 15. The toilet seat 15 includes a toilet seat main part 16,and a pair of shaft portions (rotation shaft) 17 provided near left andright ends in a width direction at a rear end portion of the toilet seatmain part 16.

The shaft portion 17 of the toilet seat 15 is inserted into an openingdescribed later and formed in the casing 11, and the toilet seat 15 isrotatably attached to the casing 11 using the shaft portion 17 as afulcrum. In the toilet apparatus 10 of the embodiment, a portion servingas a fulcrum of rotation of the toilet seat 15 is referred to as a hingeportion as well.

FIG. 1B is an enlarged view of a portion (portion A of FIG. 1A) providedwith one hinge portion in a pair of hinge portions. FIG. 1B shows statein which the toilet seat main part 16 is removed.

The one hinge portion shown in FIG. 1B is provided with a seatingdetection sensor as described later. The other hinge portion is notprovided with the seating detection sensor. Or the seating detectionsensor may be provided in the other seating detection sensor. Theseating detection sensor may be provided in at least one of the twohinge portions.

FIG. 2 is a perspective view of a portion shown in FIG. 1B as viewedfrom right side.

FIG. 3 is an A-A cross sectional view in FIG. 1B.

FIG. 4 is an enlarged view of a portion B in FIG. 3.

FIG. 5 is a B-B cross sectional view in FIG. 1B. FIG. 5 corresponds to aC-C cross sectional view in FIG. 4.

FIG. 6A is an enlarged view of an opening formation portion in thecasing 11, and FIG. 6B shows insertion of shaft portion 17 of the toiletseat 15 into an opening 20 of FIG. 6A.

As shown in FIG. 6A, the opening 20 is formed on a side face 12 of thecasing 11. In FIGS. 6A and 6B, the left side shows the front of thetoilet apparatus 10, the right side shows the rear of the toiletapparatus 10, and the lower side shows a direction of action of gravity.

A side face 21 on the front side and a side face 21 on the rear side inthe opening 20 of the toilet apparatus are a vertical surface extendingin the vertical direction. A face 22 on the upper side and a face 23 onthe lower side to the side face (vertical surface) 21 in the opening arecurved surfaces. The side face 21, the face 22 on the upper side, andthe face 23 on the lower side are continuously formed and form a contourof the opening 20.

The face 22 on the upper side is an upwardly convex curved surface, andthe face 23 on the lower side is a downwardly convex curved surface. Adistance along a horizontal direction between a pair of side faces 21 isshorter than a distance along the vertical direction between a top ofthe face 22 on the upper side and a bottom of the face 23 on the lowerside.

AS shown in FIG. 4, FIG. 5, and FIG. 6B, the shaft portion 17 of thetoilet seat 15 is formed cylindrically, and the shaft portion 17 isinserted inside the casing 11 through the opening 20. A clearancetolerating rotation of the shaft portion 17 is formed between an outercircumferential surface of the shaft portion 17 and an inner surface ofthe opening 20 (side face 21, face 22 on the upper side, and the face 23on the lower side).

For the clearance, the toilet seat 15 is slightly movable in thefront-back direction (horizontal direction in FIG. 6B) of the toiletapparatus 10. Since the shaft portion 17 abuts the side face 21 of theopening 17, the toilet seat 15 is regulated to move more in thefront-back direction.

Inside the casing 11, a position shift absorption member 30 is providedin the portion where the shaft portion 17 of the toilet set 15 isinserted, as shown in FIG. 4, FIG. 5.

FIG. 7A is a perspective view of the position shift absorption member30, and FIG. 7B is a perspective view of the position shift absorptionmember 30 as viewed from the opposite side to FIG. 7A.

The position shift absorption member 30 includes a tubular portion 31and a push portion 36, and these are provided integrally. Furthermore, aregulation means 40 is integrally provided with the position shiftabsorption member 30. The regulation means 40 may be another body to theposition shift absorption member 30.

A load receiver 35 is provided in a lower portion in the verticaldirection of the tubular portion 31. A portion of an innercircumferential surface of the tubular portion 31 is a horizontalsurface, and the horizontal surface serves as the load receiver 35. Anopening 32 is formed on one side in an axis direction of the tubularportion 31, and a cover 33 is integrally provided on the other side.

The regulation means 40 is provided below the outside of the outercircumferential surface of the tubular portion 31. The regulation means40 includes an upper face portion 41, a side face portion 42, and alower face portion 43, and these are integrally provided in a quadrangleframe shape. The lower face portion 43 is not continuous in thehorizontal direction, divided by a notch, and the side face portion 42and the lower face portion 43 are formed in an L-shape in the crosssection.

The push portion 36 is provided on a back surface of the upper faceportion 41 below the load receiver 35. The push portion 36 is providedas a protrusion portion projecting downward from the back surface of theupper face portion 41, and extends in the axis direction of the tubularportion 31.

As shown in FIGS. 6A and 6B, a holding portion 13 in a recessed shape isprovided below the opening 20 inside the side face 12 of the casing 11.The holding portion 13 is integrally provided with the casing 11.

As shown in FIG. 5, the position shift absorption member 30 is providedabove the holding portion 13 inside the side face 12 of the casing 11.As shown in FIG. 2, FIG. 4, the regulator means 40 is disposed in theholding portion 13 in a recessed shape of the casing 11. The lower faceportion 43 of the regulator means 40 is on a bottom of the holdingportion 13, and the bottom of the holding portion 13 supports theregulator means 40 and the position shift absorption member 30 in thevertical direction.

The side face portion 42 of the regulator means 40 abuts the side faceof the holding portion 13, and thus the movement of the regulator means40 and the position shift absorption member 30 in the front-backdirection (horizontal direction in FIG. 4) of the toilet apparatus 10 isregulated.

As shown in FIG. 5, the shaft portion 17 of the toilet seat 15 isinserted inside the tubular portion 13 through the opening 20 of thecasing 11 and the opening 32 of the tubular portion 13 of the positionshift absorption member 30, and the shaft portion 17 is on the loadreceiver 35 of the position shift absorption member 30.

In a state of the shaft portion 17 being on the load receiver 35, theclearance is ensured between the shaft portion 17 and the face 23 on thelower side of the opening 20 of the casing 11. That is, the load of thetoilet seat 15 in the vertical direction is not applied to the face onthe lower side of the opening 20 of the casing 11. The load receiver 35of the position shift absorption member 30 receives the load of thetoilet seat 15 in the vertical direction via the shaft portion 17.

The cover 33 is provided on an opposite side of the opening 32 in whichthe shaft portion 17 is inserted in the tubular portion 13 of theposition shift absorption member 30 as shown in FIG. 2, FIG. 5.

As shown in FIG. 4, a strain generating body 50 is held inside theregulator means 40. The strain generating body 50 is sandwiched betweenthe push portion 36 of the position shift absorption member 30 and thelower face portion 43 of the regulator means 40. A side face of thestrain generating body 50 abuts the side face portion 42 of theregulator means 40, and the movement of the strain generating body 50 inthe front-back direction (horizontal direction in FIG. 4) is regulated.That is, the relative shift in the front-back direction of the straingenerating body 50 to the push portion 36 is regulated.

The regulator means 40 is supported on the holding portion 13 of thecasing 11. Therefore, the strain generating body 50 held on theregulator means 40 is held to the casing 11 below the shaft portion 17of the toilet seat 15.

The load receiver 35 is provided between the shaft portion 17 and thestrain generating body 50, and the shaft portion 17 is on the loadreceiver 35 in contact with the load receiver 35. The push portion 36 isprovided between the load receiver 35 and the strain generating body 50.The load receiver 35 receives the load of the toilet seat 15 via theshaft portion 17, the load received by the load receiver 35 istransmitted to the push portion 36, and the push portion 36 pushes thestrain generating body 50.

The strain generating body 50 is pushed by the push portion 36 to bedeflected, and the strain is generated in the strain generating body 50.The strain generating body 50 is made of a metal material, for example,made of a stainless material. Or, the strain generating body 50 may beformed from a resin material.

FIG. 8 is a perspective view of the regulator means and the positionshift absorption member 30 in a state of holding the strain generatingbody 50 as viewed from below.

As shown in FIG. 8, a stain gauge 60 detecting a strain amount of thestrain generating body 50 is provided on a back surface (lower face) ofthe strain generating body 50. The strain gauge is formed in a regionnot covered with the lower face portion 43 of the regulator means 40 inthe back surface of the strain generating body 50. The strain gauge 60faces the bottom of the holding portion 13 shown in FIG. 4 via a space.

The strain generating body 50 and the strain gauge 60 form a seatingdetection sensor detecting seating of the user on the toilet seat 15.

FIG. 9 is a circuit block diagram of the toilet apparatus 10 of theembodiment.

The strain gauge 60 includes, for example, the configuration forming aWheatstone bridge circuit from a metal film patterned on a resin film.When a force is applied to the strain generating body 50 and the strainis generated in the strain generating body 50, a resistance value of thestrain gauge 60 changes and an output voltage of the Wheatstone bridgecircuit changes.

The output voltage of the Wheatstone bridge circuit is inputted to acontroller 90 via an amplifier 80, and the controller 90 controlsvarious instruments of the toilet apparatus 10 in response to presenceor absence of seating detection.

FIG. 10A is a view similar to FIG. 4 showing a hinge portion of theembodiment, and FIG. 10B and FIG. 10C are views of comparison examplesto FIG. 10A.

The side face 21 of the opening 20 of the embodiment shown in FIG. 10Ais a vertical surface as described before. In contrast, an opening 20′in FIGS. 10B and 10C of the comparison example has a perfect circularshape, and the side face is a curve surface.

FIG. 11A shows a state in which a user 100 sits on the front of thetoilet seat 15. FIG. 11B shows a state in which the user 100 shown inFIG. 11A shifts the weight to the rear side, and changes a sittingposition to the rear side of the toilet seat 15.

The weight shift like this to the rear side of the user 100 also movesthe shaft portion 17 of the toilet seat 15 to the rear side, the shaftportion 17 being inserted to the openings 20, 20′ of the casing 11. FIG.10A shows a state in which the shaft portion 17 abuts the side face 21on the rear side in the opening 20 due to the movement of the shaftportion 17 to the rear side, and FIG. 10B and FIG. 10C show a state inwhich the shaft portion 17 abuts the inner circumferential surface onthe rear side in the opening 20′ due to the movement of the shaftportion 17 to the rear side.

As shown in FIGS. 10B and 10C, if the shaft portion 17 abuts the curvedsurface, a partial component of a horizontal load accompanied with themovement of the shaft portion 17 to the rear side is converted to avertical load.

FIG. 10B shows an example in which the shaft portion 17 abuts a portionon the lower side of a rear side inner circumferential surface in theopening 20′, and the partial component of the horizontal load isconverted to a vertically upward load. An upward force is applied to theshaft portion 17 as a reaction from the opening 20′. For this reason, anoriginal vertically downward load A applied from the shaft portion 17 tothe strain generating body 50 via the load receiver 35 and the pushportion 36 is reduce by an upward load B (noise of vertical load)converted from the horizontal load, and then a load C smaller than theoriginal vertically downward load A becomes a detected load. That is,the strain amount of the strain generating body 50 decreases. This maylead an incorrect detection result (decrease of detection ability)indicating that despite the user is seated on the toilet seat 15, theuser does not seat from the reason that the output voltage of the straingauge 50 does not reach a seating detection voltage.

Conversely, FIG. 10C shows an example in which the shaft portion 17abuts a portion on the upper side of a rear side inner circumferentialsurface in the opening 20′, and a partial component of the horizontalload is converted to a vertically downward load. A downward force isapplied to the shaft portion 17 as a reaction from the opening 20′. Forthis reason, a downward load B′ (noise of vertical load) furtherconverted from the horizontal load is added to the original verticallydownward load A applied from the shaft portion 17 to the straingenerating body 50 via the load receiver 35 and the push portion 36.This may lead breakage of the strain generating body 50 and the straingauge 60 due to application of an excessive load C′ exceeding abreakdown load (breakdown limit) of the strain generating body 50 to thestrain generating body 50.

Also in the case where the toilet seat 15 moves to the front side andthe shaft portion 17 abuts a front side inner circumferential surface ofthe opening 20′, increase and decrease of the load to the originalvertical load may be caused by the horizontal load.

In contrast, according to the embodiment, when the shaft portion 17abuts the opening 20 due to the movement of the toilet seat 15 in thefront-back direction, a force release portion is provided, whichreleases a force (horizontal load) applied to the opening 20 from theshaft portion 17 so that the force is not converted in the verticaldirection. This force release portion is specifically the side face 21of the opening 20 formed as the vertical surface.

The side face 21 in a region (range) which the shaft portion 17 in theopening 20 is capable of abutting forms the vertical surface. For thatreason, even if the shaft portion 17 abuts the side face (verticalsurface) 21, the shat portion 17 receives just only a reaction force inthe horizontal direction from the opening 20, and does not receives theforce in the vertical direction. Therefore, the force applied in thevertical direction to the strain generating body 50 from the shaftportion 17 in a state of the shaft portion 17 not abutting the side face21 of the opening 20 does not change also in a state of the shaftportion 17 abutting the side face 21 of the opening 20, and ismaintained.

That is, the load A applied downwardly in the vertical direction to thestrain generating body 50 when the user seats on the toilet seat 15 isnot influenced by the load due to the weight shift or the like of theuser, and since the original vertical load A is surely applied to thestrain generating body 50, it is possible to detect surely seating ofthe user on the toilet seat 15. Since there is no conversion from thehorizontal load to the vertical load, the excessive load is not appliedto the strain generating body 50, and it is possible to prevent thebreakage of the strain generating body 50 and the strain gauge 60.

According to the embodiment configured like this, because the seatingdetection sensor is provided on the hinge portion that the strain amountof the strain generating body 50 is apt to be small, while the straingenerating body 50 is easy to be deflected so that even though theseating of a small load can be detected, even though the horizontal loadis generated by the weight shift or the like of the user, the load isnot transmitted to the strain generating body 50, therefore it ispossible to prevent the breakage of the strain generating body 50 andthe strain gauge 60.

That is, according to the embodiment, the side face 21 of the opening 20is simply configured to be the vertical surface, thereby the improvementof the seating detection ability to the small load is compatible withthe breakage prevention of the strain generating body 50 and the straingauge 60 due to the excessive load.

Without providing the position shift absorption member 30, the shaftportion 17 may be configured to push directly the strain generating body50. However, like the embodiment, if the load of the shaft portion 17 isset to receive by the position shift absorption member 30 once, theposition shift absorption member 30 can absorbs the position shift ofthe toilet seat 15.

Since an area of the load receiver 35 of the position shift absorptionmember 30 is broader than an area of the shaft portion 17 contacting theload receiver 35, even though the position of the shaft portion 17shifts by movement of the user during seating, the load receiver 35 canreceive surely the load due to seating of the user. Furthermore, an areaof the push portion 36 pushing the strain generating portion 50 issmaller than the area of the load receiver 35, even though the shaftportion 17 shifts, the shift of the position due to the straingenerating body 50 pushed by the push portion 36 is suppressed, and theposition shift of the shaft portion 17 does not influence the deflectionof the strain generating body 50.

That is, even if the position where the shaft portion 17 contacts theload receiver 35 varies, the load in the vertical direction istransmitted to a specified region of the strain generating body 50 fromthe push portion 36 independently on the contact position of the shaftportion 17. The deflection (strain amount) of the strain generating body50 is not influenced by the position of the shaft portion 17, butdepends on the magnitude of the load in the vertical direction.

In the case where without providing the position shift absorption member30, the shaft portion 17 is configured to push directly the straingenerating body 50, for example, there is a possibility that if thecontact position of the shaft portion 17 shifts toward the end from thecenter portion of the strain generating body 50, the strain generatingbody 50 cannot deflect sufficiently and the strain amount necessary fordetection may not be detected.

In contrast, if the position shift absorption member 30 is provided,also in the case where the shaft portion 17 is located on the centerportion of the strain generating body 50 and in the case where the shaftportion 17 is located toward the end of the strain generating body 50,the push portion 36 pushes the same specified region of the straingenerating body 50, the strain generating body 50 deflects in a similarway, and the strain amount detected by the strain gauge 60 becomes thesame as well. Even if the user moves during seating and the shaftportion 17 shifts toward the end of the strain generating body 50, thedeflection (strain) necessary for seating detection can be generated inthe strain generating body 50, and it is possible to detect surelyseating of the user on the toilet seat 15.

FIGS. 12A to 12C are schematic views showing other examples of theopening formed in the casing 11 and having the shaft portion 17 of thetoilet seat 15 inserted.

A side face 121 of an opening 120 shown in FIG. 12A is not a verticalsurface but a curved surface. A curvature of the side face 121 issmaller than a curvature of a surface on an upper side and a curvatureof a surface on a lower side of the opening 120. Even if the side face121 where the shaft portion 17 is capable of abutting is a curvedsurface, if the curvature is small, the magnitude of the force convertedin the vertical direction when the shaft portion 17 abuts the side face121 can be small. Even if the side face of the opening is not a perfectvertical surface and has a slight curvature, it is sufficient as long asan increase/decrease width to the original vertical load applied to thestrain generating body 50 can be suppressed within a range that does notinfluence the seating detection and the breakdown load of the straingenerating body 50.

From such a standpoint, an inclination angle θ of the side face 121 fromthe vertical direction is preferable to be not more than 10°, furtherpreferable to be not more than 5°. The θ represents the inclinationangle from the vertical direction (dotted line) of a line approximatedby a straight line of the side face 121 indicated as a curved surface ina plan view of the opening 120 or a tangential line at an arbitrarypoint.

It is sufficient that a shape (contour) of the opening is rotatable inas state in which the shaft portion 17 is inserted into the opening. Forexample, as shown in FIG. 12B, it may be a rectangular opening 220. Theopening 220 has a side face 221 which is a vertical surface as well asthe opening 20 of the above embodiment, furthermore a surface on anupper side and a surface on a lower side are continuous planar surfacesforming a right angle to a side face 221.

Like an opening 320 shown in FIG. 12C, a side face 321 may be a curvedsurface becoming a mountain toward the inside the opening 320. Also inthis case, as described previously, the inclination angle θ from thevertical direction of the side face 321 is preferable to be not morethan 10°, furthermore preferable to be not more than 5°.

FIG. 13A is a schematic cross sectional view along a vertical directionof a hinge portion of other embodiment, and FIG. 13B is a partial crosssectional side view as viewing a left side to a D-D line in FIG. 13A.

In the hinge portion as shown in FIGS. 13A and 13B, a shaft portion 151is provided in a casing 150, and an opening 170 into which the shaftportion 151 is inserted is formed on the toilet seat 15 side.

The toilet seat 15 includes the toilet seat main part 16 shown in FIG.1A and a hollow shaft portion 160 shown in FIG. 13A, and the toilet seatmain part 16 is combined with the hollow shaft portion 160. The opening170 is formed in the hollow shaft portion 160, and the shaft portion 151of the casing 150 is inserted into the opening 170.

The hollow shaft portion 160 is rotatable around the shaft portion 151,and consequently the toilet seat 15 rotates using the shaft portion 151of the casing 150 as a fulcrum.

The strain generating body 50 is held on an inner wall of the hollowshaft portion 160 on the toilet seat side. The strain gauge 60 isprovided on the upper surface of the strain generating body 50. Thestrain generating body 50 is provided above the shaft portion of thecasing 150, and the position shift absorption member 30 is providedbetween the strain generating body 50 and the shaft portion 151.

The hollow shaft portion 160 of the toilet seat 15 holding the straingenerating body 50 is on the shaft portion 151 of the casing 150 via theposition shift absorption member 30. That is, the shaft portion 151 ofthe casing 150 receives the vertically downward load of the toilet seat15 via the position shift absorption member 30, and generates the strainin the strain generating body 50. The strain amount of the straingenerating body 50 is detected by the strain gauge 60.

Due to the movement of the toilet seat 15 in the front-back direction(horizontal direction in FIG. 13B), the hollow shaft portion 160 of thetoilet seat 15 moves in the front-back direction, and the shaft portion151 of the casing 150 is capable of abutting a side face 171 of theopening 170.

As shown in FIG. 13B, the side face 171 of the opening 170 is a verticalsurface. For that reason, as described previously, even if the shaftportion 151 abuts the side face (vertical surface) 171 of the opening170, the load in the horizontal direction is not converted to the loadin the vertical direction. Therefore, since the load applied to thestrain generating body 50 in the vertical direction when the user seatson the toilet seat 15 is not influenced by the load due to the weightshift or the like of the user in the front-back direction, and theoriginal vertical load is applied surely to the strain generating body50, it is possible to detect surely seating of the user on the toiletseat 15. Since the vertical load converted to the horizontal load is nottransmitted to the strain generating body 50, the excessive load is notapplied to the strain generating body 50 and it is possible to preventthe breakage of the strain generating body 50 and the strain gauge 60.

The embodiments of the invention have been described with reference tothe specific example. However, the invention is not limited thereto.Various variations are possible on the basis of the technical idea ofthe invention.

What is claimed is:
 1. A toilet apparatus comprising: a casing; a toiletseat attached rotatably to the casing, an opening being provided on oneof the casing or the toilet seat, a shaft portion being provided on oneother of the casing or the toilet seat, the shaft portion being insertedinto the opening, the shaft portion being capable of abutting theopening by movement of the toilet seat in a front-back direction; aseating detection sensor detecting seating of an user on the toiletseat, the seating detection sensor including a strain generating bodyand a strain gauge, the strain generating body being held on the casingor the toilet seat, the strain generating body receiving a load from thetoilet seat via the shaft portion to generate a strain, the strain gaugebeing provided on the strain generating body and detecting a strainamount of the strain generating body; and a force release portionreleasing a force applied to the opening in a horizontal direction fromthe shaft portion in a state of the shaft portion abutting the openingso that the force is not converted downwardly in a vertical direction.2. The toilet apparatus according to claim 1, wherein the opening isprovided in the casing, the shaft portion is provided in the toiletseat, and the strain generating body is held to the casing below theshaft portion.
 3. The toilet apparatus according to claim 2, wherein theforce release portion maintains a force applied from the shaft portionto the strain generating body in a vertical direction in a state of theshaft portion not abutting the opening also in a state of the shaftportion abutting the opening.
 4. The toilet apparatus according to claim3, wherein the force release portion is a vertical surface of theopening, the shaft portion being capable of abutting the verticalsurface.
 5. The toilet apparatus according to claim 1, wherein the forcerelease portion maintains a force applied from the shaft portion to thestrain generating body in a vertical direction in a state of the shaftportion not abutting the opening also in a state of the shaft portionabutting the opening.
 6. The toilet apparatus according to claim 5,wherein the force release portion is a vertical surface of the opening,the shaft portion being capable of abutting the vertical surface.